This invention relates to an ultrasonic signal processing apparatus for use in ultrasonic flaw detection wherein an ultrasonic pulse is transmitted from an ultrasonic transducer and an echo from a defect in a workpiece is received so as to detect the defect, the apparatus operating to convert into a digital signal the echo signal reflected from the defect in the workpiece.
A prior-art ultrasonic signal processing apparatus which converts into a digital signal an echo signal reflected from a defect in a workpiece and delivers the digital signal as an output is disclosed in, for example, U.S. Pat. No. 3,872,715 entitled "ULTRASONIC PULSE-ECHO GATE CIRCUIT."